1. Field of the Invention
The subject invention relates to a fluid heat exchanger for cooling an electronic device.
2. Description of the Prior Art
The operating speed of computers is constantly being improved to create faster computers. With this, comes increased heat generation and a need to effectively dissipate that heat.
Heat exchangers and heat sink assemblies have been used that apply natural or forced convection cooling methods to dissipate heat from electronic devices that are highly concentrated heat sources such as microprocessors and computer chips. These heat exchangers typically use air to directly remove heat from the electronic devices; however air has a relatively low heat capacity. Thus, liquid-cooled units called LCUs employing a cold plate in conjunction with high heat capacity fluids have been used to remove heat from these types of heat sources. Although LCUs are satisfactory for moderate heat flux, increasing computing speeds have required more effective heat sink assemblies.
Accordingly, thermosiphon cooling units (TCUs) have been used for cooling electronic devices having a high heat flux. A typical TCU absorbs heat generated by the electronic device by vaporizing a working fluid housed on the boiler plate of the unit. The boiling of the working fluid constitutes a phase change from liquid-to-vapor state and as such the working fluid of the TCU is considered to be a two-phase fluid. Vapor generated during boiling of the working fluid is then transferred to a condenser, where it is liquefied by the process of film condensation over the condensing surface of the TCU. The heat is rejected into a stream of air flowing through a tube running through the condenser or flowing over fins extending from the condenser. Alternatively, a second refrigerant can flow through the tube increasing the cooling efficiency. The condensed liquid is returned back to the boiler plate by gravity to continue the boiling-condensing cycle.
An example of a cooling system for electronic devices is disclosed in U.S. Pat. No. 5,529,115 to Paterson.
The Paterson patent discloses an assembly for cooling an electronic device including a housing partially filled with a refrigerant wherein heat generated by the electronic device dissipates into the housing causing the refrigerant to boil. A conduit extends through the housing and air flows through the conduit. The vapors boiled off the refrigerant then rise upwardly and condense on the ceiling of the housing and on the outside surface of the conduit. The conduit extends linearly through the housing and is partially submerged in the refrigerant.
Although the prior art dissipates heat from electronic devices, as computing speeds increase, there is a continuing need for cooling devices having more efficient and/or alternative heat transfer capabilities as compared to the conventional electronic cooling assemblies.